/Engine/Plugins/Experimental/GeometryScripting/Source/GeometryScriptingCore/Public/GeometryScript/GeometryScriptSelectionTypes.h
Call PerVertexFunc for each VertexID in the Selection. For Triangle Selections, Triangles Vertex tuples are enumerated and accumulated in aTSet. For PolyGroup Selections, a full mesh iteration is used to find all Triangle Vertices in the groups (accumulated in aTSet)
void ProcessByVertexID ( const [UE::Geometry::FDynamicMesh3](API\Runtime\GeometryCore\DynamicMesh\FDynamicMesh3) & Mesh, [TFunctionRef](API\Runtime\Core\GenericPlatform\TFunctionRef)< void(int32)> PerVertexFunc, bool bProcessAllVertsIfSelectionEmpty ) const